Field of the Invention
The present invention generally relates to dental medicine and provides a method for machining a ceramic implant or a ceramic attachment element, for creating an inner structure.
Description of Related Art
Implants manufactured of ceramic are known from the state of the art and, in particular, due to their extraordinary biocompatibility and aesthetic advantages, are often preferable for dental-medical applications compared to conventional implants of titanium and titanium alloys.
Ceramic implants, as is known, are manufactured of oxide ceramics, for example of ceramic based on zirconium oxide or aluminium oxide. The manufacture of implants of titanium or titanium alloys and of ceramic implants is different. The ceramic material is particularly hard and cannot be machined with the same techniques as are common with metal machining. In particular, ceramic material cannot be punched or turned due to its brittle characteristics. The usually applied material-removing methods, in particular grinding for creating outer contours or inner contours of ceramic implants are comparatively time-consuming and thus expensive.
EP 2 072 020 describes such a method for manufacturing dental-medical products of ceramic such as implants, bridges, attachment elements (abutment). In this method, firstly a ceramic green compact containing a binder is manufactured firstly by way of pressing a ceramic powder for example at 180 to 300 MPa. This green compact is machined for example by way of cutting or grinding. The binder is not removed until after this machining when sintering. Further steps of grinding at increasing speeds and with an initially larger diameter of the milling tool are described for increasing the machining efficiency.
Grinding methods with rotating pins are common for creating fine contours and in particular inner contours. This machining step is time-consuming, since ceramic material is often removed only at the end face of the pin, or perpendicularly thereto, wherein in both cases, very little ceramic material is removed per unit of time. Such grinding steps therefore slow down the production of ceramic implants. For this reason, the manufacture of such inner contours with ceramic implants also entails a significantly increased cost factor in comparison to the manufacture of inner contours with conventional implants of titanium or titanium alloys.